Exploring Neurotransmitter Dynamics: A Systematic Review of BDNF, IL-6, and TNF Biomarkers in Brain Health and Function

Biomarkers are very critical for the rational development of medical therapeutics but there is significant confusion that persists on the definition and concept involved in clinical practice and research, mainly in the field of nutrition and chronic diseases. Various autoimmune disorders like AHT (Autoimmune Hypothyroidism) is associated with occurrence and developing of depression. Depression is associated with changing levels of trophic factors and inflammatory factors-IL-6, TNF-alpha, bdnf, crp. Relationship between the coexistence of depression and aht indicates the etiology and pathomechanism of depression. Bidirectional relationship between cvd(cardiovascular disease) and depression suggests bdnf as reliable biomarker for prediction of cvd and depression, as it plays an important role in growth and survival. The aim of this systematic review is to understand the normal levels of BDNF, IL-6, TNF-alpha and to systematically study the elevated and decreased levels of each biomarkers. Also to examine the association of the changing levels of the biomarkers with underlying diseases-cvd, aht, depression. Methods: systematic study was carried out to obtain the relevant information. Results: abnormally low level of bdnf is associated with depression and simultaneously high levels of IL-6, TNF. Severity of depression is high in patients with elevated antithyroid antibodies and aht. This helps for better understanding of interrelationship between them and is very helpful in pharmacotherapy.